Removal and recovery of p-phenylenediamines developing compounds from photofinishing lab-washwater using clinoptilolite tuffs from Greece

Clinoptilolite tuffs from areas in Thrace region of Greece are compared wit h synthetic zeolites NaY and NH4Y for the uptake of N4-ethyl-N4-(2-methansu lphonamidoethyl)-2-methyl-1,4-phenylenediamin (sesquisulphate, monohydrate) with the trade name CD-3 for the purpose to be used for clean-up and recyc ling photo-finishing and photo-developing washwaters. The cation-exchange c apacity is found to be 6.15-11.1 mg/g for zeoliferous tuffs at equilibrium concentration of 50 ppm CD-3 in aqueous solution compared to 65.0 mg/g of N aY and 48.2 mg/g for NH4Y synthetic zeolites corresponding to the removal o f CD-3 from 120 to 2001 of 50 ppm aqueous solution per kg of natural zeolif erous tuff; this capacity is only 6-10 times lower than type-Y synthetic ze olite. Initial rates of uptake are 20.8 mg/l/min for natural and 38.5 mg/l/ min for synthetic zeolites. Regeneration levels of 55, 23, 35, and 33% are obtained for MCH, SF, NaY, and NH4Y, respectively. The rapid and almost com plete uptake of CD-3 from its aqueous solutions at low CD-3 concentrations by the natural zeolites is promising for such an application. (C) 2001 Else vier Science Ltd. All rights reserved.